Cannula having a wire that extends along said cannula

Abstract

A cannula has an electrically conductive material that runs along the cannula. This material has an electrical terminal, which can be wired or wirelessly connected with a measuring device. This makes it possible to acquire the position of the cannula in a human body, and generate a warning signal given a dislocation of the cannula.

The invention claimed is: 
     
       1. A cannula with an electrically conductive material that runs along the cannula,
 wherein the material has an electrical terminal; 
 wherein the cannula has an outer jacket and an inner jacket, which are electrically insulating, and between which the electrically conductive material is arranged such that the electrically conductive material is guided in a cannula wall and radially outwardly and radially inwardly insulated by a tubular wall; 
 wherein the electrically conductive material extends in the cannula wall over an area along the cannula from the cannula tip to the electrical terminal; and 
 wherein the cannula is adapted such that, when arranged in a body vessel, the outer jacket of the cannula acts as a dielectric, with the electrically conductive material corresponding to a first electrode, and the body vessel to a second electrode, such that the position of the cannula inside of a body part relative to an electrical contact surface can be measured. 
 
     
     
       2. The cannula according to  claim 1 , wherein the material is cylindrical in design along the cannula. 
     
     
       3. The cannula according to  claim 1 , wherein the material has a wire. 
     
     
       4. The cannula according to  claim 3 , wherein the wire is spirally wound. 
     
     
       5. The cannula according to  claim 1 , wherein the cannula has a transmitter that is connected with the electrical terminal. 
     
     
       6. The cannula according to  claim 1 , wherein the electrical terminal has a sliding contact. 
     
     
       7. The cannula according to  claim 6 , wherein the sliding contact is designed as an electrically conductive ring. 
     
     
       8. The cannula according to  claim 7 , wherein the electrically conductive ring is designed as a conical sleeve. 
     
     
       9. The cannula according to  claim 1 , wherein the cannula has an RFID element, which is connected with the electrical terminal in an electrically conductive manner. 
     
     
       10. The cannula according to  claim 1 , wherein the cannula has another electrical terminal that has no electrically conductive connection to the wire. 
     
     
       11. The cannula according to  claim 1 , wherein the cannula has a cable and a plug or a bushing, wherein there is an electrically conductive connection between the plug or the bushing and the cable, and between the cable and the electrical terminal. 
     
     
       12. A cannula system with the cannula according to  claim 1 , further comprising an electrical contact surface that can be fastened to a body surface and a measuring device that is electrically connected with the electrical contact surface and the terminal. 
     
     
       13. The cannula system according to  claim 12 , wherein the measuring device is a measuring device for determining the electrical capacitance. 
     
     
       14. The cannula system according to  claim 12 , wherein the electrical contact surface has a transmitter. 
     
     
       15. The cannula system according to  claim 12 , wherein the cannula system has a computer and a signaling device which are connected with the measuring device. 
     
     
       16. The cannula system according to  claim 15 , wherein the signaling device has several different signal transmitters.